A traditional electronic cigarette (“e-cigarette” or “e-Cig”) is a device that emulates tobacco cigarette smoking, by producing smoke replacement that may be similar in its physical sensation, general appearance, and sometimes flavor (i.e., with tobacco fragrance, menthol taste, added nicotine etc.). A battery portion of the e-Cig includes a controller and battery for powering the device and a cartomizer portion generates an aerosol mist (i.e. vapor) that is a replacement for cigarette smoke. In particular, the cartomizer may use heat (e.g. a heating element), ultrasonic energy, or other means to vaporize a liquid solution or “e-Liquid” (for example including propylene glycol, or glycerin, for example including taste and fragrance ingredients) into an aerosol mist. The component in the cartomizer portion that generates the aerosol mist may be referred to as an aerosol mist generator. The e-Cig may be powered by a power source, such as a battery which provides current for the heating. The power source may be difficult to regulate and result in a shorter life-span for the e-Cig by requiring re-charging.
The e-Liquid may be kept in a small container (sometimes called “cartomizer”, which may be the approximate size of a regular cigarette's filter), and during the puff some of it is heated while being close to and around a heating coil (for example operated by a battery, and controlled via a control chip and a puff sensor). The heated e-Liquid loses its high viscosity, and then is prone to vaporization and some evaporation, generating the “smoke” to be inhaled by the user.
The vaporization may be enhanced by the usage of an e-Liquid-soaked wick inside a heating coil, wherein the small spaces between the wick fibers and small spaces inside the wick fibers enhance the breaking of the heated e-Liquid to small droplets generating the fog-like smoke. Some of the vaporized e-liquid may re-condensate to droplets, creating more fog-like smoke, due to the mix of the inhaled room-temperature air with the heated air and vapor inside the cartomizer. The fog-like smoke effect can also be enhanced by the high temperatures generated by the electrically-energized heated coil, combined with air flow (that reduces pressure around the wick due to the Bernoulli's principle, thus enhancing evaporation rate) which both enhance evaporation rate, and thereby load the air around the heating coil and wick with e-Liquid vapors. When the air round the heating coil and wick is saturated with e-Liquid vapors, and is hit by the room-temperature air flow sucked in by the user, some of its vapor may condensate into small air-borne droplets (similar to water fog in air) and add to the “smoke” generated by the e-Cig.
A unique problem that may arise due to the fog-like smoke effect mechanism of operation may include the depletion of high-boiling-temperature components in the vapors (low boiling temperature components boil first), wherein the high-boiling-temperature components may be lacking in the re-condensed droplets and fog. This may be of interest concerning e-Cigs with nicotine, wherein the nicotine has relatively high boiling points; the possibly re-condensed fog will be weak in nicotine, negating the effects expected by the user. Low nicotine absorption may be an issue with e-Cigs. The fact that the vaporized “smoke” can be generated from nicotine-depleted re-condensed vapor may at least partially explain it.
In some embodiments, the entire e-Liquid containing volume in the e-Cig, and its surrounding walls and other parts, are heated by the heating coil during the smoking puffs' duration. Eventually the entire e-Cig mouthpiece may feel warm in the hand and mouth of a user, and sometimes the e-Cig mouthpiece may even get overheated. Still, only the e-Liquid volume that is close to the heating coil and wick combination may generate most of the “smoke”. Even the e-Liquid that is soaked in the wick, which may be heated by the heating coil, can be about twenty times or more in quantity than the e-Liquid that is eventually vaporized by the heating coil.
The growing popularity of e-Cigs emphasizes some of the challenges the industry faces, including the need for longer life-span, more efficient e-Cigs, and the environmental impact of used and discarded e-Cigs. There are several considerations to consider to overcome the challenges the industry faces, including: e-Cigs that are more energy-efficient, better e-Cig life span, reduced cost, ability to use smaller and lighter batteries, lighter e-Cigs (making the e-Cig more similar to regular cigarettes, which are lightweight), reduced waste, and possibly better control methods and user experience design.